Testing a dryer is necessary to evaluate its absolute and comparative performance with other dryers. A conventional flat plate continuous pistachio dryer was tested by a new practical method of mass and energy equilibrium. Results showed that the average power consumption and heat loss in three tests are 62.13 and 18.99 kW, respectively. The ratio of heat loss on power consumption showed that the efficiency of practical pistachios flat plate dryer is about 69.4%. (C) 2011 Elsevier Ltd. All rights reserved.